1. Field
The invention is in the field of medical emergency detection and response systems.
2. State of the Art
In the United States today there are approximately 400,000 incident congestive heart failure patients who are at extreme risk of sudden cardiac arrest/sudden cardiac death or heart attack, and about five million prevalent patients who are at high risk. About 350,000 people a year in the United States die from some type of cardiac arrest/sudden cardiac death. One of the main causes of sudden cardiac arrest/sudden cardiac death is the arrhythmia termed ventricular fibrillation. The quivering ventricles suspend the ability of the heart to act as a hemodynamic transfer pump thus stopping blood flow in the body. Without blood flow, various organs of the body, and especially the brain, are deprived of oxygen and glucose. When deprived of oxygen and glucose, the brain will start to loose both its cognitive ability or capability and its stimulative and integrative functions. The extent of this brain loss is time dependent becoming mostly irreversible after five minutes, and with possible total loss of brain function usually between seven and eight minutes. For every minute that elapses after normal blood flow ceases, the chance of survival diminishes by seven to ten percent. Survival rates for people who suffer sudden cardiac arrest/sudden cardiac death outside of a hospital are estimated to be as low as 1.4 percent. Thus, quick response to the loss of heart beat is critical if a patient is to survive and be functional. The use of CPR is merely a first aid response that usually buys only a few minutes for the person whose heart is beating erratically.
The AED or automatic external defibrillator is a device or machine to stop ventricular fibrillation and has been perfected to be used by individuals who are not medically trained. Usually these individuals are locally trained in the use of the AED machine. Thus, police and fire personnel, security officers, and lay persons with some background can effectively use currently available AED's. As AED's further develop, their use will be more and more simplified. AED machines are currently available that can be operated by untrained persons by merely reading simple instructions on the AED or listening to voice instructions generated by the AED during use. The major problems, however, are the recognition of the need to defibrillate (use the AED) and the response time to get an AED machine to a person in need of defibrillation once the need is recognized. In recognizing the need, the person suffering the need has to be noticed. Generally such person will fall to the ground from lack of muscular response. The person is noticed by spectators or bystanders, called a witnessed event, who eventually recognize that a problem exists. A telephone call to 911 or other emergency service is made and the journey to the scene by the emergency response personnel begins. While many emergency response agencies tout a three to four minute response time, this time is from when they are notified of the emergency. If two or three minutes have already passed before such agency receives notice of the emergency, the three or four minute response time is not fast enough.
Compounding the problem is the finding that at least thirty five percent of persons suffering sudden cardiac arrest/sudden cardiac death and maybe as high as seventy to eighty percent are unwitnessed, such as at night or when a person is not at home or unwitnessed in hospitals or nursing homes. Such persons may often be beyond any hope of revival by the time they are discovered.
There is currently a move in the United States to make AED's more available and accessible. The Government is planning to place AED's in public buildings such as airports and Federal buildings, and local communities are similarly attempting to make AED's available in public places and in police cars. A major US airlines is joining three foreign airlines in placing an AED on each of its aircraft. A life was reported saved shortly thereafter as a result. However, even with increased availability of AED's, detection and recognition of those needing treatment is critical. Further, being able to find an AED machine if one is located nearby is also critical.
Various monitoring systems have been proposed to monitor persons, such as persons having implanted medical devices, for among other things, emergency medical situations. For example, U.S. Pat. No. 6,083,248 assigned to Medtronic, Inc. discloses a system for monitoring and reprogramming implanted medical devices such as heart pacemakers and pacemaker-cardioverter-defibrillator combinations. The system transmits signals representative of operation of the monitored device to a medical support network or location which can remotely keep track of the operation of the implanted device and can remotely reprogram the device. The system also keeps track of the location of the person with the device through various locating systems such as a global positioning system (GPS) or other known system. The described system can also alert emergency medical personnel upon detection of an emergency situation and guide such emergency medical personnel to the person involved. However, although such system monitors implanted heart devices and detects heart conditions, the alarm indications are sent to the medical support network, which may be remote from the victim, and response time remains a problem. This response time is a problem even in notification through a 911 network which is contemplated by the patent. Various other monitoring systems such as shown in U.S. Pat. No. 6,073,046, also have similar problems.